The present invention relates to a rotatable cutter spindle for cutting wooden chips of a predetermined length.
In order to produce flat chips of high quality it has been known for a long time to provide a cutter spindle in which a cutter is arranged on a supporting body inclined relative to the axis of the latter. In such a case, a pulling cut is performed which guarantees a wooden chip with a smooth cutting surface and a high quality upper surface. Such a cutter spindle is disclosed in the German Pat. No. 1,251,937.
In the known cutter spindles a so-called toothed cutter has been used. It is formed as a strip-shaped cutter whose radially outer portions are provided with cutting edges. Each of the toothed cutters removes a material along the region corresponding to half of the cutter length. In order to guarantee a complete material removal, the toothed cutters are offset relative to one another by half of the tooth length. The length of the chips is determined by the portion of the cutters provided with the cutting edges, so that when such cutters are utilized a splitting cutter can be abandoned which latter was necessary in the cases when cutters with continuous cutting edges were utilized.
The cutter spindles with toothed cutters inclined relative to the spindle axis have been proved to be satisfactory for manufacturing high quality flat chips for many years. The only adherent disadvantages thereof are constituted by the fact that they have relatively small material removal capacity inasmuch as in order to cut over the entire length of the cutter spindle it is necessary to have two cutters, and that the number of the cutters to be mounted to the cutter spindle is limited on construction grounds. Purely theoretically it is possible to double the material removal capacity for a given cutter spindle, when the toothed cutter can be replaced with a cutter with continuous cutting edges. However, a splitting cutter which has to be provided in such a case occupies an additional space. The splitting cutter is expensive and involves expensive manipulations for insertion of the same into the cutter spindle inasmuch as this cutter, similarly to the chip cutter, becomes quickly blunted and as a rule must be replaced by a new one. Moreover, the splitting knife affects the desirable support of wood before the chip cutter and increases the separation of the material.
Some other cutter spindles are disclosed in the German Design Patent MR No. 52 published in 1957, in the German Pat. Nos. 936,294 and 2,241,938, and in the German Auslegeschrift Nos. 1,021,565 and 1,076,936.